Julie Bauer spent two decades working at some of the world's largest advertising agencies, serving some of the world's biggest brands. Now, as a founding partner (along with Tod Seisser and Steve Landsberg) of the New York City-based ad firm Grok, Bauer is facing off against those same big names. And winning.Entrepreneur Julie Bauer told her story to Inc. reporter April Joyner.

My partners and I all came out of 20-plus years working for big agencies. A lot of people take clients with them when they leave an agency, but we didn't. We thought there was an opportunity to go to smaller, challenger brands and say, "You're going to get the same type of talent that Procter & Gamble gets when it walks through the doors of a Saatchi or a BBDO."

Because we know how the big guys operate, we can zig when they zag. For example, we are the agency for i-Health, which makes a probiotic supplement called Culturelle. In mid-2009, Procter & Gamble entered the probiotics market with a product called Align.

We knew P&G would come in with a hardcore scientific story and base all of their marketing around that claim. And sure enough, they did. They ran ads stating that Align was the No. 1 recommended probiotic by gastroenterologists. And they offered heavy promotion pricing--they were basically giving their products away to build market share. We were outspent 3 to 1.

We didn't want to back away from the science--the bacterial strain in Culturelle is clinically proven--but we also felt there was a beauty and softness to the Culturelle brand. So we built our marketing around talking to women about digestive issues and making them feel good about Culturelle's ability to relieve them.

We toned down the website's color scheme and focused on making it soothing, comforting. We ran commercials on TV, and we launched an educational website. Though Culturelle lost its No. 1 place in the market for a year, we stuck to our guns. I'm proud to say that Culturelle has regained its position as the No. 1 brand in probiotics.

One of our clients once told me that the reason she likes working with Grok is that we're simpatico--we're doing the same things she is. Just like we have to compete with the big agencies to get business, our clients come to us for the marketing muscle to compete with large businesses. If you look at the definition of grok, that's what it is: It's a sci-fi term that means "to understand something or someone profoundly and intuitively." And that's what we do.